The hydrosilylation of alkenes is a widely practiced catalytic transformation, and is of great importance for the production of organosilanes and materials based on poly(siloxane)s (Selected Reviews for Hydrosilylation: (a) Marciniec, B. in Hydrosilylation: A Comprehensive Review on Recent Advances; Marciniec, B., Eds., Springer, Netherlands, 2009, Chapter 1. (b) Troegel, D.; Stohrer, J. Coord. Chem. Rev. 2011, 255, 1440. (c) Roy, A. K. Adv. Organomet. Chem. 2008, 55, 1. (d) Marciniec, B. Coord. Chem. Rev. 2005, 249, 2374. (e) Ojima, I.; Li, Z.; Zhu, J. The Chemistry of Organic Silicon Compounds, Wiley: Avon, 1998; Chapter 29. (f) Marciniec, B.; Gulinski, J.; Urbaniak, W.; Kornetka, Z. W. Comprehensive Handbook on Organosilicon Chemistry; Pergamon: Oxford, 1992. (g) Lewis, L. N.; Stein, J.; Gao, Y.; Colborn, R. E.; Hutchins, G. Platinum Metals Rev. 1997, 41, 66-75. (d) Marciniec, B. In Applied Homogeneous Catalysis with Organometallic Compounds, second ed.; Cornils, B.; Herrmann, W. A., Eds., Wiley-VCH, Weinheim, 2002. (h) Reichl, J. A.; Berry, D. H. Adv. Organomet. Chem. 1999, 43, 197. (i) Roy, A. K. Adv. Organomet. Chem. 2008, 55, 1). For industrial applications, the most common and active hydrosilylation catalysts are based on platinum, and to a lesser degree other precious metals. Selective examples: (a) Speier, J. L.; Webster, J. A.; Barnes, G. H. J. Am. Chem. Soc. 1957, 79, 974. (b) Speier, J. L.; Hook, D. E. Dow Corning Corp., U.S. Pat. No. 2,823,218 A 1958. (c) Karstedt, B. D. General Electric Company, U.S. Pat. No. 3,775,452 A 1973. (d) Chalk, A. J.; Harrod, J. F. J. Am. Chem. Soc. 1965, 87, 16. (e) Seitz, F.; Wrighton, M. S. Angew. Chem. Int. Ed. Engl. 1988, 27, 289. (f) Duckett, S. B.; Perutz, R. N. Organometallics 1992, 11, 90. (g) LaPointe, A. M.; Rix, F. C.; Brookhart, M. J. Am. Chem. Soc. 1997, 119, 906. (h) Glaser, P. B.; Tilley, T. D. J. Am. Chem. Soc. 2003, 125, 13640. Due to the high cost associated with such metals, there is increasing interest in utilization of less expensive first-row transition metal catalysts for this transformation. Early examples of using first-row transition metal carbonyl compounds for hydrosilylation catalysis under high temperature or photo irradiation conditions: (a) Nesmeyanov, A. N.; Freidlina, R. K.; Chukovskaya, E. C.; Petrova, R. G.; Belyaysky, A. B. Tetrahedron 1962, 17, 61; (b) Reichel, C. L.; Wrighton, M. S. Inorg. Chem. 1980, 19, 3858. There has been some progress toward this goal, including the work of Brookhart and coworkers on the cationic Cp*Co system for the catalytic hydrosilylation of 1-hexene with Et3SiH (Brookhart, M.; Grant, B. E. J. Am. Chem. Soc. 1993, 115, 2151). In addition, Chirik et al. have reported neutral bis(imino)pyridine iron bis(dinitrogen) complexes as catalyst precursors for the hydrosilylation of a variety of alkenes with PhSiH3 (hydrosilylations with Ph2SiH2 appear to be much slower) ((a) Bart, S. C.; Lobkovsky, E.; Chirik, P. J. J. Am. Chem. Soc. 2004, 126, 13794; (b) Delis, J. G. P.; Chirik, P. J.; Tondreau, A. M. Momentive Performance Materials Inc., U.S. Pat. No. 0,009,565 A1 2011; (c) For a recent report on Fe-catalyzed regioselective diene hydrosilylation: Wu, J. Y.; Stanzl, B. N.; Ritter, T. J. Am. Chem. Soc. 2010, 132, 13214). Catalytic systems based on indenyl nickel complexes have also been reported for the regioselective hydrosilylation of styrene with PhSiH3 ((a) Fontaine, F.-G.; Nguyen, R.-V.; Zargarian, D. Can. J. Chem. 2003, 81, 1299; (b) Chen, Y.; Sui-Seng, C.; Boucher, S.; Zargarian, D. Organometallics 2005, 24, 149: Hyder, I.; Jimenez-Tenorio, M.; Puerta, M. C.; Valerga, P. J. Chem. Soc. Dalton Trans. 2007, 3000). Other nickel(II) and nickel(0) complexes such as [Ni(PPh3)2Cl2] and [{Ni(η-CH2═CHSiMe2)2O}2{μ-(η-CH2═CHSiMe2)2O}] exhibit activity toward hydrosilylation, but these reactions are typically associated with harsh reaction conditions or limited substrate scope, and often mediate extensive dehydrosilylation (Marciniec, B.; Maciejewski, H.; Kownacki, I. J. Organomet. Chem. 2000, 597, 175) and/or silane redistribution ((a) Kiso, Y.; Kumada, M.; Tamao, K.; Umeno, M. J. Organomet. Chem. 1973, 50, 297; (b) Kiso, Y.; Kumada, M.; Maeda, K.; Sumitami, K.; Tamao, K. J. Organomet. Chem. 1973, 50, 311) as processes that compete with hydrosilylation. Thus, the development of generally effective and useful alkene hydrosilylations using first-row metals such as manganese, iron, cobalt and nickel is still at a very early stage.
There are several industrially important catalytic processes employing phosphorus ligands. For example, U.S. Pat. No. 5,910,600 to Urata, et al. discloses that bisphosphite compounds can be used as a constituting element of a homogeneous metal catalyst for various reactions such as hydrogenation, hydroformylation, hydrocyanation, hydrocarboxylation, hydroamidation, hydroesterification and aldol condensation.
U.S. Pat. No. 5,512,696 to Kreutzer, et al. discloses a hydrocyanation process using a multidentate phosphite ligand, and the patents and publications referenced therein describe hydrocyanation catalyst systems pertaining to the hydrocyanation of thylenically unsaturated compounds. U.S. Pat. Nos. 5,723,641, 5,663,369, 5,688,986 and 5,847,191 disclose processes using zero-valent nickel and multidentate phosphite ligands.
U.S. Pat. No. 5,821,378 to Foo, et al. discloses reactions that are carried out in the presence of zero-valent nickel and a multidentate phosphite ligand. PCT Application WO99/06357 discloses multidentate phosphite ligands having alkyl ether substituents on the carbon attached to the ortho position of the terminal phenol group.
Though first row metals supported on phosphorus-based ligands are known to have catalytic activity, such compounds have not been applied to the hydrosilyation of pi-bonded species.
Hydrosilylation reactions are recognized high-value reactions in industry and in the laboratory. Currently, industrially relevant hydrosilylation reactions are performed utilizing precious metal-based catalysts. Hydrosilylation catalysts based on first-row metals would provide entry into valuable hydrosilylated compounds in a cost-effective manner. Moreover, the use of certain first-row metals presents the opportunity to perform hydrosilylation using environmentally friendly catalysts (e.g., Fe-based). The present invention provides such catalysts.
The introduction of cationic first row metal compounds, which are effective, general catalysts for the hydrosilylation of alkenes and other pi-bonded species would provide a significant advance in the art. Quite surprisingly, the present invention provides such catalysts and method of using these catalysts to effect hydrosilylation across pi-bonds.